
/* Copyright (c) Mark J. Kilgard, 1994. */

/*
 * (c) Copyright 1993, Silicon Graphics, Inc.
 * ALL RIGHTS RESERVED
 * Permission to use, copy, modify, and distribute this software for
 * any purpose and without fee is hereby granted, provided that the above
 * copyright notice appear in all copies and that both the copyright notice
 * and this permission notice appear in supporting documentation, and that
 * the name of Silicon Graphics, Inc. not be used in advertising
 * or publicity pertaining to distribution of the software without specific,
 * written prior permission.
 *
 * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
 * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
 * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
 * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
 * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
 * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
 * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
 * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN
 * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
 * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * US Government Users Restricted Rights
 * Use, duplication, or disclosure by the Government is subject to
 * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
 * (c)(1)(ii) of the Rights in Technical Data and Computer Software
 * clause at DFARS 252.227-7013 and/or in similar or successor
 * clauses in the FAR or the DOD or NASA FAR Supplement.
 * Unpublished-- rights reserved under the copyright laws of the
 * United States.  Contractor/manufacturer is Silicon Graphics,
 * Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311.
 *
 * OpenGL(TM) is a trademark of Silicon Graphics, Inc.
 */
/*  mipmap.c
 *  This program demonstrates using mipmaps for texture maps.
 *  To overtly show the effect of mipmaps, each mipmap reduction
 *  level has a solidly colored, contrasting texture image.
 *  Thus, the quadrilateral which is drawn is drawn with several
 *  different colors.
 */
#include <stdlib.h>
#include <GL/glut.h>

GLubyte mipmapImage32[32][32][3];
GLubyte mipmapImage16[16][16][3];
GLubyte mipmapImage8[8][8][3];
GLubyte mipmapImage4[4][4][3];
GLubyte mipmapImage2[2][2][3];
GLubyte mipmapImage1[1][1][3];

static void makeImages(void)
{
    int i, j;

    for (i = 0; i < 32; i++) {
	for (j = 0; j < 32; j++) {
	    mipmapImage32[i][j][0] = 255;
	    mipmapImage32[i][j][1] = 255;
	    mipmapImage32[i][j][2] = 0;
	}
    }
    for (i = 0; i < 16; i++) {
	for (j = 0; j < 16; j++) {
	    mipmapImage16[i][j][0] = 255;
	    mipmapImage16[i][j][1] = 0;
	    mipmapImage16[i][j][2] = 255;
	}
    }
    for (i = 0; i < 8; i++) {
	for (j = 0; j < 8; j++) {
	    mipmapImage8[i][j][0] = 255;
	    mipmapImage8[i][j][1] = 0;
	    mipmapImage8[i][j][2] = 0;
	}
    }
    for (i = 0; i < 4; i++) {
	for (j = 0; j < 4; j++) {
	    mipmapImage4[i][j][0] = 0;
	    mipmapImage4[i][j][1] = 255;
	    mipmapImage4[i][j][2] = 0;
	}
    }
    for (i = 0; i < 2; i++) {
	for (j = 0; j < 2; j++) {
	    mipmapImage2[i][j][0] = 0;
	    mipmapImage2[i][j][1] = 0;
	    mipmapImage2[i][j][2] = 255;
	}
    }
    mipmapImage1[0][0][0] = 255;
    mipmapImage1[0][0][1] = 255;
    mipmapImage1[0][0][2] = 255;
}

static void myinit(void)
{
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LESS);
    glShadeModel(GL_FLAT);

    glTranslatef(0.0, 0.0, -3.6);
    makeImages();
    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
    glTexImage2D(GL_TEXTURE_2D, 0, 3, 32, 32, 0,
		 GL_RGB, GL_UNSIGNED_BYTE, &mipmapImage32[0][0][0]);
    glTexImage2D(GL_TEXTURE_2D, 1, 3, 16, 16, 0,
		 GL_RGB, GL_UNSIGNED_BYTE, &mipmapImage16[0][0][0]);
    glTexImage2D(GL_TEXTURE_2D, 2, 3, 8, 8, 0,
		 GL_RGB, GL_UNSIGNED_BYTE, &mipmapImage8[0][0][0]);
    glTexImage2D(GL_TEXTURE_2D, 3, 3, 4, 4, 0,
		 GL_RGB, GL_UNSIGNED_BYTE, &mipmapImage4[0][0][0]);
    glTexImage2D(GL_TEXTURE_2D, 4, 3, 2, 2, 0,
		 GL_RGB, GL_UNSIGNED_BYTE, &mipmapImage2[0][0][0]);
    glTexImage2D(GL_TEXTURE_2D, 5, 3, 1, 1, 0,
		 GL_RGB, GL_UNSIGNED_BYTE, &mipmapImage1[0][0][0]);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
	GL_NEAREST_MIPMAP_NEAREST);
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
    glEnable(GL_TEXTURE_2D);
}

static void display(void)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glBegin(GL_QUADS);
    glTexCoord2f(0.0, 0.0); glVertex3f(-2.0, -1.0, 0.0);
    glTexCoord2f(0.0, 8.0); glVertex3f(-2.0, 1.0, 0.0);
    glTexCoord2f(8.0, 8.0); glVertex3f(2000.0, 1.0, -6000.0);
    glTexCoord2f(8.0, 0.0); glVertex3f(2000.0, -1.0, -6000.0);
    glEnd();
    glFlush();
}

static void myReshape(int w, int h)
{
    glViewport(0, 0, w, h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(60.0, 1.0*(GLfloat)w/(GLfloat)h, 1.0, 30000.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}

static void
key(unsigned char k, int x, int y)
{
  switch (k) {
  case 27:  /* Escape */
    exit(0);
    break;
  default:
    return;
  }
  glutPostRedisplay();
}

int main(int argc, char** argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
    glutInitWindowSize (500, 500);
    glutCreateWindow (argv[0]);
    myinit();
    glutReshapeFunc (myReshape);
    glutDisplayFunc(display);
    glutKeyboardFunc(key);
    glutMainLoop();
    return 0;             /* ANSI C requires main to return int. */
}
